The invention relates to a brake pad holder of a disc brake, in particular for a commercial vehicle.
It is known from German patent document DE 40 20 287 A1 to provide each of the two brake pads used in a disc brake, for positional securing thereof, with a respective pad-holding spring. The pad holding spring is fastened to the brake pad in the upper edge region oriented towards an assembly opening of the brake caliper in such a manner that it is pressed under preload into the pad shaft of a positionally fixed brake anchor plate (carrier) or of a brake caliper by a pad-holding clip. The pad holding clip extends transversely to the brake pads, that is, in the axial direction of the brake disc. In this case, the pad-holding clip is fastened in two opposite regions of the caliper bounding the assembly opening.
The known pad-holding clip is configured as a sheet metal part and has a substantially rectangular cross section, so that the pad-holding clip bears against the pad-holding spring with its flat underside surface.
In operation, relative movement may occur between the pad-holding clip and the pad-holding spring transversely to the longitudinal extent of the pad-holding clip, resulting in additional stresses on the parts concerned, for example abrasion of surface coatings which ultimately influence corrosion behavior.
In addition to these functional disadvantages, the known brake pad holder, because of its configuration, does not offer any assurance that brake pads which are unsuitable for the brake model concerned are not installed.
Thus, brake pads, the installed height of which is less than that of the appropriate brake pads, can be readily used, so that the brake pads and their pad-holding springs are then not contacted and held under preload by the pad-holding clip. The desired effect of the use of the pad-holding clip, namely tolerance-compensation and reduction or prevention of clatter noises that can occur during operation of the vehicle, is not produced in this case. In principle, any brake pad which does not exceed a minimum height can be installed.
It is the object of the invention to develop a brake pad holder and a brake pad system such that its operating safety is improved and its service life is increased.
This object is achieved by a brake pad holder of a disc brake, in particular for a commercial vehicle, wherein brake pads assigned to both sides of a brake disc are retained by a respective pad-holding spring in a spring-loaded manner in a pad shaft of a positionally fixed brake anchor plate or of a brake caliper. A pad-holding clip, which extends in the axial direction of the brake disc and is fastened to the brake caliper, is supported on the brake pads. The pad-holding clip has at least one limb extending approximately radially in relation to the brake disc and projecting into a recess of at least one brake pad. It is further achieved with a brake pad of a disc brake, in particular for a commercial vehicle, with a lining carrier plate, a friction lining fastened thereon, and a pad-holding spring connected to the lining carrier plate. At least one of the pad-holding spring, the lining carrier plate and the friction lining have a common recess disposed transversely to their longitudinal extent.
A brake pad holder configured in this manner increases the operating safety of the overall disc brake, since only brake pads intended for a particular brake model can now be used. In this respect, the inventive configuration of the brake pad holder constitutes a coding. Brake pads which do not have a recess into which the new pad-holding clip can be inserted cannot be installed, since the pad-holding clip cannot then be fitted. The fact that brake pads are components relevant to safety, which must also be correctly installed, imparts special importance to the invention and the effect achievable thereby.
The same applies to the relative movement between the pad-holding clip and the pad-holding spring in the circumferential direction of the brake disc now occurring in operation, that is during braking, since the brake pad is held in a practically form-fitting manner by the engagement of the pad-holding clip.
The special stress on the components, that is, the pad-holding spring and the pad-holding clip, caused hitherto by the relative movement no longer arises, resulting in a very noteworthy increase in the service life of these components; one factor among others contributing to this increase is the fact that surface coatings of these components are not worn away, which components are therefore exposed to no further risk of corrosion.
According to an advantageous development of the invention it is provided that an angled limb of the pad-holding clip, which engages in the recess of the brake pad adapted thereto, is provided only in the lining carrier plate. However, in principle it is also possible to configure the limb in such a manner that it also engages in a recess of the friction lining material.
A further aspect of the invention provides that the limb of the lining-holding clip, which limb is angled generally radially in relation to the axis of rotation of the brake disc, is provided with a scaling, for example in the form of scale marks by which wear of the brake pad or of its friction lining can be easily detected. Of course, this also contributes to an increase in the operating safety.
In this connection it should be emphasized that this control possibility can be achieved practically without any special complexity and cost regarding the design and manufacture, and that wear detection can be carried out easily. For this purpose, viewing through the assembly opening of the brake caliper is sufficient, through which both the brake pads and the pad-holding clip which bridges the assembly opening can be easily seen.
In relation to the longitudinal axis of the pad-holding clip, limbs arranged offset to one another may be provided on both sides thereof, one limb engaging in the brake pad arranged on the brake-application side of the disc and the other limb, arranged on the opposite longitudinal side, engaging in the reaction-side brake pad. This is especially advantageous if the brake pads are identical.
In principle, it is also possible to arrange the two limbs, each associated with a respective brake pad, on one longitudinal side of the pad-holding clip or at the center thereof. In all cases, in addition to the brake pad, the associated pad-holding spring should also be shaped correspondingly, such that it projects into the recess of the brake pad.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.